The invention generally relates to devices that are actuated using a field responsive material, and more specifically the invention relates to a joint that includes a field responsive material and method for selectively and releasably joining at least two discrete members in fixed abutment along discrete member binding edges.
Field responsive devices include a volume of a field responsive material such as a magnetorheological (MR) fluid to control the motion of such devices. Magnetorheological fluid may be comprised of either a volume of magnetizable particles or more frequently may be comprised of magnetizable particles suspended in a viscous liquid carrier such as oil, water or silicone. In either its dry form or liquid form, the MR fluid functions in a similar manner. During use, when a magnetic field is applied across the MR fluid, the suspended particles are magnetized and as a result are held in place by the applied magnetic field and the magnetized fluid assumes an apparent solid state. When the magnetic field is removed, the MR fluid returns to its pre magnetized state comprised of dry loose particles or a liquid.
Known field responsive devices are typically comprised of rotary and linear acting motion control devices where the rotary devices frequently include brakes, clutches and the like for providing variable torques while linear acting devices can be used for damping linear motion or for providing controllable dissipative forces along a specified axis. In known field responsive devices the field is applied across the material in a precise manner to accurately control the forces and torques supplied by such devices. The field responsive devices provide the torques and forces supplied by conventional mechanically actuated devices and as a result, in known linear and rotary devices the mechanical componetry is replaced by a volume of field responsive material and a means for intermittently supplying a field across the material. By incorporating field responsive material in known mechanical devices the mechanical design is simplified, and in most instances because the mechanical componetry is replaced by a field responsive material the field responsive devices have a longer useful life than the mechanically actuated counterpart devices.
In addition to the foregoing, it would be beneficial to use the field responsive material in a joint for connecting discrete members. By incorporating a volume of a field responsive material in a joint, mechanical fasteners and other components may be eliminated and the discrete members could be connected and disconnected easily and reliably.
The foregoing illustrates limitations known to exist in present devices and methods. Thus it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
In one aspect of the invention this is accomplished by providing a temporary joint that includes a volume of field responsive material. The temporary joint comprises a first discrete member having a first edge and a first movable coupling means; and a second discrete member having a second edge and a second movable coupling means.
When it is necessary to form a joint between the first and second discrete members, the first and second edges are moved into abutment to define a binding edge. Then, the first and second movable coupling means are moved toward the binding edge; and the temporary joint is formed when the first and second movable coupling means are proximate the binding edge. When the coupling means are in the required locations, a magnetic field is applied across the field responsive material so that the field responsive material approaches a near solid state. The joint is broken by moving one or both of the first and second coupling means away from the binding edge.
In another aspect of the invention the first coupling means is a volume of magnetorheological fluid and the second coupling means is a magnet.
The foregoing and other aspects of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures.